1. Field of the Invention
The present invention concerns a method for operating an x-ray device, in particular a mammography x-ray apparatus, of the type that emits an x-ray beam that exhibits a movement in the manner of a scan of a subject.
2. Description of the Prior Art
In x-ray imaging, the imaging properties are negatively influenced (such as blurring) by the scatter radiation of the x-ray beam generated by an anode, for example a rotary anode. To prevent such scatter radiation, in addition to scattered-ray grids scan methods are used in which a fan-shaped x-ray beam is excised from the totality of emitted, x-rays by a slit-shaped diaphragm, and the diaphragm and the x-ray beam are moved in a grid-like manner over the subject to be imaged. Furthermore, to prevent scatter radiation it is known to provide a further slit diaphragm between the subject and the radiation detector that converts the x-ray radiation into an image signal. It is also known to divide the detector into row-like regions and to only map the respective region passed over by the x-ray beam. It cannot be prevented, however, that regions of the x-ray beam that produce a different image resolution are gated by means of the movement of the diaphragm, such that the generated image exhibits differing image definitions.
An x-ray device for implementing a scanning method is known from U.S. Pat. No. 4,928,297, in which an x-ray tube, a slit-shaped diaphragm and a row-like detector are arranged in a line and are fastened together on a shaft. This unit is mounted such that it can rotate around an axis intersecting the line, above the x-ray tube. The necessary synchronization of the mechanical movements is thereby made particularly simple.